1. Field of the Invention
The present invention relates to a charged particle beam drawing apparatus having a cleaning mechanism, and an article manufacturing method using the same.
2. Description of the Related Art
In recent years, as micronization of elements, increasingly complex circuit patterns, or a higher capacity of pattern data advance, the drawing accuracy as well as drawing throughput of charged particle beam drawing apparatuses for use in the manufacturing of devices such as semiconductor integrated circuits needs to be improved. However, if an electron lens positioned above a substrate to be treated is formed with, for example, fine apertures (holes), secondary electrons emitted from a resist and an out gas act with each other, and thus, contamination (decomposition product) adheres to the surface of and inside the apertures. Accumulations of such contamination may significantly affect on the drawing position accuracy, aberration, and the like of the electron lens. Thus, Japanese Patent Laid-Open No. 8-139010 discloses a charged beam apparatus that has a gas generation unit for generating gas for removing internal contamination consisting at least one of the plasma or radicals (active species) and cleans a portion of an interior of the apparatus using the generated plasma or radicals.
However, in the charged beam apparatus disclosed in Japanese Patent Laid-Open No. 8-139010, the conductance of fine apertures provided in the electron lens is small, and thus, radicals may be deactivated or radicals may not sufficiently reach such contamination. Consequently, such contamination may not be sufficiently cleaned.